Resolved! I use 100Khz oscillator for LSE on STM32H7B0VBT6 but LSERDY cannot work
100khz Oscillator for LSE input. The OSCillator works right bcz I test the waveform by scope.but stm32h7b0vb cannot get lserdy bit set.Seems I m the 1st Person meet the situation.plz help me. Thanks.